Bochi



"Nbv. 29, 1949 A. BUCHI Re. 23,172

COOLING DEVICE FOR TURBINE ROTORS Original Filed Oct. 15, 1941 2Sheets-Sheet l NOV. 29, 1949 Uc Re. 23,172

COOLING DEVICE FOR TURBINE ROTORS Original Filed Oct. 15, 1941 2Sheets-Sheet 2 Yrzven for:

UNITED STATES PATENT OFFICE COOLING DEVICE FOR TURBINE BOTOBS AlfredBiiebi, Winterthur, Switzerland Original No. 2,384,189, dated December5, 1944,

Serial No. 415,136, October 15, 1941. Application for reissue December13, 1947, Serial No. 791,673. In Switzerland September 21, 1840 scum(ciao-41) This invention relates to cooling devices for turbine rotorsfor hot power fluids.

According to the present invention, on the disc of the bucket wheel orturbine rotor, cooling fan biading is arranged, which has the functionto sweep and cool the wheel disc of the turbine rotor and the bucketarrangement connected thereto, by the delivery of said biading providingthe cooling means.

The arrangement may be such that the cooling medium delivered by the fanbiading also imparts inherent energy to the turbine buckets and Ispassed from the inlet to the exit side of the turbine bucket arrangementat the region of the base portions of the buckets. However, part of thedelivery of the cooling fan means may be blown through passages disposedadjacent to the point of connection of the turbine. buckets with theturbine rotor, by which provision the bucket connecting means areadditionally cooled and heat conduction towards the body of the turbinerotor is prevented.

'Ihe turbine rotor may be provided with fan biading onlyonthat of itsend faces adjacent the inlet side of the turbine for the power fluid, oron both'end faces. Exteriorly beyond the cooling fan biading difluser or"guide vanes may be arranged in the stationary part of the turbinecasing surrounding the turbine rotor, for conveying the cooling meanstowards the bucket arranger'nent of the turbine. For the purpose ofobtaining eflective transmission of heat from the turbine rotor to thecooling means the fan blades are made integral with the turbine rotor.The

fan biading employed may be of any suitable type and the disposition ofthe biading may be chosen to suit requirements.

The bearing arrangement of the turbine rotor may be such that the rotorprojects freely therefrom with one rotor end face unobstructed so thatcooling air can be directly guided towards the cooling fan biading fromwithout unimpeded.

In the accompanying drawings embodiments 2 situated at theinlet side ofthe turbine for the power fluid.

In Fig. 1, the turbine rotor is designated by I, whereas the numeral 2denotes the blower rotor driven by the turbine rotor. A two-part cooledturbine casing I surrounds the blower rotor. The numerals I and 5 referto the gas supply conduits leading into the turbine and the nozzleringrespectively, the gases being rojected onto the bucket arrangement 8 ofthe turbine rotor I through said ring. The intake of the blower isdesignated by I, and 8 refers to the diffuser casing of the blower. Theturbine rotor I has its bearings 9, II in a bearing sleeve I2 inside ofa stationary bearing support I I within the blower casing, and theblower rotor 2 is connected to the turbine rotor I by a sleeve-likeextension II.

The invention is concerned with the cooling fan biadings I I and I4arranged on,either end face of the turbine rotor I, as shown in Fig. 1.

- By the action of the biadings I4, I! the cooling medium, which may beair or the like, is sucked in in the region of the hub portion oftheblower rotor, and is conveyed towards the outer end face of theturbine rotor. During the passage of the air through the bladings Itand/or II this air first cools the bucket wheel disc I and keeps oncooling in this way until it leaves the biading II or I4 respectively.Thereupon the cooling air, when leaving the biading II, is deflected bythe stationary difluser biading I5 into the rotating bucket arrangement6 of-the' turbine rotor I, so that a film of cold air is blown throughthe bucket arrangement in between the hot power gases, which passthrough the turbine bucket arrangement 8 at a point disposed radiallyfurther outward, and the base extensions I8 of the buckets. By thismeans not only the end walls of the turbine rotor, the base extensionsI9 and the inner portions II of the buckets are cooled, but the heatflux passing from the hot gases conveyed through the outermost portionsof the buckets 8 towards the body of the rotor I is considerably reducedat the same time and the radially outer bucket portions are also cooled.Cooling air is supplied from without at the inlet side of the turbinethrough the supply funnel I8, if, as shown in Fig. 1, a, freelyprojecting turbine wheel with an unobstructed outer end face is used.

The air drawn in and delivered by the cooling fan biading II is suppliedto the latter from without through bores 25. The numeral I5 refers tocooling air dlfluser blades being, for example. arranged exteriorly ofth fan rotor in the stationary part of the turbine, and. if desired,sunk in the material-of said part. The diffuser blades I deflect the airdelivered by the blading I4 to the right in Fig. 1 into the innerportion of the turbine buckets 8, advantageously, at such an angle thatin addition to producing a cooling eflect this air imparts inherentenergy thereof to the turbine rotor I. In order to provide fordefleeting the cooling air with as little loss of energy as possible onthe turbine rotor I at a point radially beyond the cooling fan bladingII a thickened portion I1 aerodynamically improving the deflecting ofthe cooling medium into the difl'user blades I5 may be arranged on oneor both end faces of said rotor.

Fig. 2 is a view of a segment of the turbine bucket arrangement on alarger'scale showing the path along which the cooling air flows throughthe turbine bucket arrangement 6. The radially inner portions I Ii ofthe turbine bucket arrangement 6 are cooled by the air passing out ofthe diffuser blading I5 for the cooling air. The base extensions I! ofthe turbine buckets 8 are so shaped that adiacent to the joints 2| between the individual buckets and, upon choice, also in the adioiningportions of the turbine rotor I, passages 20 are formed through which atleast part of the air output of the cooling fan is conveyed towards theexit side of the turbine buckets 6. Bv this means the base extensions I9and the radially outer ortions of the turbine rotor I are cooled. Inorder that the turbine bucket arran ement 6 is nevertheless. flrmlvsecured'to the turbine rotor I the arran ement is so chosen thatadiacent turbine buckets touch each other on the outside of the surfaces2i.

In an arrangement of the base portions I 9 as shown in Fi 2, forexample, also the cylindrical base extensions 22 of the buckets areprovided with passages 23. Throu h the passages 23 a a in the directionfrom the turbine rotor, together further portion of the air delivered bythe cooling fan will pass and thus additionally cool the base extensionsis directly, wherebv the turbine rotor I is cooled indirectly. inaddition. By virtue of the cooling thus provided not only thetemperature of the turbine rotor and that of the base extensions isbrought down and, consequently. greater strength of material is obtainedfor these parts even at high temperatures of the power gas, but alsoreduced straining due to ex ansion by heat of the parts fitted togetherresults. and imaroved resistivity of the assembly at the sameAlternativelv. part of the cooling air at least may, as also shown inFig. 2. be passed through bores 26 provided in the turbine buckets 6which bores receive, for example, the cooling air leaving the passages20, or other cooling air. By this means the buckets 6 are directlyadditionally cooled over all the length thereof and, advantageously,near their entrance portions for the hot gases.

In Fig. 3 the cooling fan blades. which are designated by ll, arepreferably in the form of radial blades for reasons of strength. Thisblade arrangement ensures minimum straining of the turbine rotor and, ifmade integrally with the turbine rotor I. maximum heat transmission fromthe rotor to the cooling medium is ensured at the same time. By the flowof air passing through between the blades I4 and II the turbine rotor issatisfactorily cooled.

In Fig. 4 the stationary difluser blade arrangement I! for deflectingthe cooling air into the turbine bucket arrangement 8 is shown, as seenwith the nozzle-like bladin 5 for the power fluid oi the turbine, whichblading is disposed radially outwardly and guides the entering hotgases.

Fig. 5 shows an exhaust gas turbine driven blower having a cooling fanblading I4 only on the end face of the rotor I adjacent the gas inletside of the turbine.

The invention can be applied also to turbines into which the power fluidis introduced in various other directions of flow, and may further beapplied to individual rotors or all the rotors of multi-stage turbines.The invention has the great advantage that a considerable proportion ofthe energy consumed i'or theconveyance oi' the cooling medium isrecovered and any substantial losses, due to change of direction of floware avoided.

Owing to the temperature of the cooling medium rising already while thelatter cools the turbine rotor disc, the gathering up of heat by saidmedium is more effective than if the cooling medium would be conductedinto the turbine bucket arangement directly from outside without beingpreheated.

I claim:

1. In a cooling device for turbine rotors for hot power fluids, aturbine rotor having a discshaped wheel body, a bucket arrangementdisposed on said wheel body, cooling fan blading means provided on saidwheel body in driving association with said rotor for delivering acooling fluid, a casing for said rotor having inlet and outlet ports forpassing hot power fluids through the bucket arrangement, said casin alsoincluding side walls, the wall on the inlet side of the turbineproviding conduction means for said cooling fluid, delivered by said fanblading means for directing the cooling fluid outwardly, sweeping andthus cooling said wheel body and then changing the direction of flow ofthe cooling fluid at the periphery of the wheel body so as to passthrough the rotor between the buckets and inwardly oi. the hot powerfluids to form a cooling and insulating layer to cool and protect theroots of the buckets and the rotor body from hot power fluids andflow-directing means arranged in the conduction means of the casingexteriorly beyond said cooling fan blading means immediately adjacentthe rotor body for guiding said cooling fluid in a direction to assistrotation of the rotor.

2. In a cooling device for turbine rotors for hot power fluids, aturbine rotor having a discshaped wheel body, a bucket arrangementdisposed on said wheel body, cooling fan blading means provided on saidwheel body in driving association with said rotor for delivering acool-' ing fluid, a casing for said rotor having inlet and outlet portsfor passing hot power fluids through the bucket arrangement, said casingalso including side walls, the wall on the inlet side of the turbineproviding conduction means for said cooling fluid, delivered by said fanblading means for directing the cooling fluid outwardly. sweeping andthus cooling said wheel body and then changing the direction of flowsans ately adjacent the rotor body for guiding said cooling fluid in adirection to assist rotation of the rotor, and thickenings disposed onan unobstructed end face of said rotor, in advance of said inclinedvanes as regards the flow of said cooling fluid, for aerodynamicallyimproving the passage of said flow into said inclined vanes.

3. In a cooling device for turbine rotors for hot power fluids, aturbine rotor having a disc-shaped wheel body, a bucket arrangementdisposed on said wheel body, cooling fan blading means provided on saidwheel body in driving association with said rotor for delivering acooling fluid, a casing for said rotor having inlet and outlet ports forpassing hot power fluids through the bucket arrangement, said casingalso including side walls, the wall on the inlet side of the turbineproviding conduction means for said cooling fluid, delivered by said fanblading means for directing the cooling fluid outwardly, sweeping andthus cooling said wheel body and then changing the direction of flow ofthe cooling fluid at the periphery of the wheel body so as to passthrough the rotor between the buckets and inwardly of the hot powerfluids to form a cooling and insulating layer to cool and protect theroots of the buckets and the rotor body from hot power fluids,flow-directing vanes arranged in the conduction means of the casingexteriorly beyond said cooling fan blading means immediately adjacentthe rotor body for guiding said cooling fluid in a direction to assistrotation of the rotor, and thickenings disposed on both end faces ofsaid rotor radially outwardly of said fan blading means in opposition tothe cooling fluid inlet end of said vanes, for aerodynamically improvingthe flow of cooling fluid toward the turbine exit.

4. In a cooling device for turbine rotors for hot compressed powerfluids, a turbine rotor having a wheel body adjacent at least one sideof which cooling fluid is adapted to be admitted, a

peripheral bead-like diverting edge on said wheel body, a casingcovering a cooling fluid inlet side of said wheel body and having inletand outlet ports for the hot power fluids, a bucket arrangement on saidwheel body surrounding said edge and having concave buckets, lateralcooling blower blading means on said rotor body blowing said coolingfluid in a substantially axial direction through said rotor in a generalcourse continually leading toward said outlet port, a pertion'at leastof said cooling fluid moving across said bead-like diverting edge towardthe inner bucket portions in an aerodynamically improved flow by virtueof said bead-like edge, a depressed annular face on said casing having aradially outer cross sectional curvature inclining toward the axialdirection, difluser blades arranged on said annular face, and a difluserassembled-of said bead-like edge and said difl'user blade car yingannular face, the said difluser pressing said cooling fluid flow throughthe inner bucket portions in work producing contact therewithindependently of the power fluid flowing through the outer bucketportions and modifying the flow properties of said cooling fluid inaccordance with those of said power fluid for preventing said two fluidsfrom admixing in said buckets.

5. In a cooling device for turbine rotors for hot compressed powerfluids, a turbine rotor having a wheel body adjacent at least one sideof which cooling fluid is adapted to be admitted, a peripheral coolingfluid diverting edge on said wheel body, a cooling fluid inlet side ofsaid having inlet and outlet ports-for the hot power fluids, a bucketarrangement on said wheel body surrounding said edge and having concavebuckets, a base extension on the individual buckets anchored in theperipheral portion of said wheel body, said peripheral wheel bodyportion having passages between adjacent ones of said base extensionsadapted to pass a portion of said cooling pressure fluid axially throughfrom one wheel face to the other for cooling the discharge ends of saidbuckets, another cooling fluid portion moving across said diverting edgetoward the inner bucket portions, a diffuser, formed by said divertingedge together with cooperative means on said casing, the said difiuserpressing said cooling fluid flow through the inner bucket portions inwork producing contact therewith independently of the power fluidflowing through the outer bucket portions and modifying the flowproperties of said cooling fluid in accordance with those of said powerfluid for preventing said two fluids from admixing in said buckets.

6. In a cooling device for turbine rotors for hot power fluids, aturbine rotor having a discshaped wheel body, a bucket arrangementdisposed on said wheel body, cooling fan blading means provided on saidwheel body in driving association with said rotor for delivering acooling medium, a casing for said rotor having inlet and outlet portsfor passing hot power fluids through the bucket arrangement, said casingalso including side walls, the wall on the inlet side of the turbineproviding conduction means for said cooling medium, delivered by saidfan blading means for directing the cooling medium outwardly, sweepingand thus cooling said wheel body and then changing the direction of flowof the cooling medium at the periphery of the wheel body so as to pass,as seen in an axial section through the turbine rotor, axially acrossthe rotor periphery to form a cooling and insulating layer to cool andprotect the roots of the buckets and the rotor body from the hot powerfluids, and flow-directing vanes arranged in the conduction means of thecasin exteriorly beyond said cooling fan blading means immediatelyadjacent the rotor body for guiding said cooling ,medium into saidbucket arrangement in the direction, but inwardly of the movement of thehot power fluids passing through said bucket arrangement.

ALFRED Bticm.

REFERENCES CITED The following references are of record in the flle ofthis patent:

uurrsn s'ra'rns rams Germany Oct. 8, 1938

